Todd Bishop at Geekwire noticed that Google's quarterly earnings filing this afternoon had a surprise: the company took a $500 million charge during the first quarter to cover a potential antitrust settlement with the Department of Justice.

$500 million isn't a huge number for Google, but it knocked the quarter's earnings down from the previously reported $2.3 billion to $1.8 billion.

Regulators are looking at complaints from competitors that Google favors its own sites in its search results.

The filing says that Google doesn't expect the eventual outcome of the DoJ investigation to have a material effect on its earnings.

But DoJ is probably the least of Google's legal problems right now: the agency approved Google's $700 million buyout of travel information company ITA, subject to certain conditions. But Google is facing an active antitrust investigation in Europe, and the Federal Trade Commission is reportedly considering launching one in the U.S.